The first attempts will be to standardize plaque samples on the basis of dry weight, DNA, and viable count. Further analyses will be made of the metabolic end products of plaque with various carbohydrate substrates. In addition to this, we hope to quantitate the teichoic acid content of plaque samples from animals. A second phase of this project is an analysis of the total energy requirements of plaque. When humans or animals are fed by stomach tube so that there are no food accumulations in the mouth, substantial amounts of plaque still form. We intend to determine molar growth yields on pure cultures of plaque microorganisms using the carbohydrate moieties found in the salivary glycoproteins as substrates. Analogous experiments will be done using plaque samples from animals.